Field of the Invention
The present invention relates generally to the problem of retrofitting fluorescent light fixtures with light emitting diode (“LED”) conversion kits and, in particular, to retrofitting troffer style fluorescent lighting fixtures with an LED conversion kits.
Background of the Invention
A troffer is a rectangular fluorescent light fixture that typically fits into a modular dropped ceiling grid and is the most common type of light fixture for use in commercial office spaces, schools, and industrial facilities. In the United States, standard troffer sizes are 1′×4′, 2′×2′ and 2′×4′, but may also be formed in other sizes. Standard troffer fixtures are typically designed to accommodate standard fluorescent lamps, i.e. T12, T8, or T5 fluorescent tubes. Troffers are typically recessed sitting above the ceiling grid, but are also available in surface mount “versions.” A typical fluorescent light troffer fixture will include hardware for mounting the tubes and a power supply or ballast configured for operating the fluorescent lights. The ballast and associated wiring will often be hidden under a channel attached to the troffer.
Functional fluorescent lights were first developed around the turn of the last century. Many early designs were attempted including the design disclosed in U.S. Pat. No. 865,367, entitled Fluorescent Electric Lamp, which issued to Thomas Edison in 1907. Modern fluorescent lamps entered widespread use in 1938 when lamp designs by the General Electric Company and the Sylvania Lighting Company were first introduced to the market. Fluorescent lamps offered several advantages over the then prevailing incandescent lamps including longer life, lower operating costs and cooler operating temperatures. As such, fluorescent lamps became the mainstay lighting source for offices, schools and most industrial facilities. The presently installed base of troffer style fluorescent lamps likely numbers in the tens, if not hundreds of millions.
Recently, LED's which emit an intense bright white light have been developed. LED based lights have several advantages over earlier fluorescent lamps. In particular, LEDs offer greater light output, energy savings, longer life, minimal degradation of light color temperature or lumen output over time, and LED lights contain no environmental contaminants such as mercury or lead, as is the case with fluorescent tubes.
However, the expense of replacing an entire light fixture previously installed may make taking advantage of the improvements offered by LED lights cost prohibitive. Recently, efforts have been made to retrofit previously installed fluorescent light fixtures to provide a less expensive way to take advantage of new LED lighting technology.
Light fixture retrofitting is the practice of replacing or eliminating components in an existing fluorescent light fixture housing, i.e. a troffer, and retrofitting LED components to provide the light fixture with the advantages of LED based lights, i.e. improved light output, energy savings and longer life. Many current retrofitting solutions are overly complex in design, often requiring lengthy and complex installation procedures. The longer the installation of a retrofit solution takes, the less likely that the retrofit solution will make economic sense for the owner of the previously installed light fixture.
Most prior art solutions involve removing the fluorescent tubes, ballast, connectors, and any other non-necessary hardware found in the original troffer, as discussed in the examples below.
One prior art solution tries to fasten a light bar composed of LEDs into a troffer by the use of self-tapping sheet metal screws in the top of the troffer housing. This method is both difficult to install and service. In addition, protection from the elements (water and dust intrusion) is lost when new hole(s) to accommodate the self-tapping screws are drilled into the fixture. Finally light output may not be optimized due to the distance from the light source to the lens.
Another similar prior art solution mounts one or more led strips to a curved flexible reflector and fastens the reflector to the troffer by the means of self-tapping screws through the top of the troffer. Here again, this solution is difficult to install, service and transport. Again protection from the elements is lost with new holes having to be drilled into the troffer housing. Again, light output may not be optimized due to the distance from the light source to the lens.
Another prior art solution attempts to remove the existing door of a specific brand of troffer and re-insert a new retrofit system back in its place by reusing the existing slots designated for the original door's hinge and latch mechanism. This solution cannot universally fit all troffers because door size, slot placement and slot size vary by manufacturer. In addition, there are safety concerns because the original slots were not designed to hold the additional weight of an LED retrofit assembly.
Another prior art solution also attempts to remove the existing door of a troffer and insert a new retrofit system back in its place using an adaptor bracket. Here again, installation is difficult and again protection from the elements, i.e. water and dust instruction, is lost if new holes are drilled into the fixture.
What is needed in the art is an LED retrofit kit that is relatively inexpensive and easy to install in a wide variety of existing troffers without the need to drill holes in the existing troffer housing.